To meet the needs for high degree of integration and miniaturization of semiconductor elements in recent years, multilayer resist methods which may readily achieve a high aspect ratio with high dimensional accuracy have been investigated for the purpose of forming a micropattern. As a resist material for use in this multilayer resist method, one having a bilayer structure including a positive type resist layer as the upper layer, and an organic resin layer as the lower layer has been examined. For the positive type resist layer as this upper layer, use of a silicon-containing polymer compound with high resistance to oxygen plasma has been studied.
As a composition for such a positive type resist, for example, a chemically amplified composition that includes a base resin having a property to increase the solubility in an aqueous alkaline solution by the action of an acid, an acid generator that generates an acid in response to an electromagnetic wave or the like, and a nitrogen-based organic basic compound (quencher) having a carbamate group, an amide group or the like which can control diffusion of acid from the acid generator may be used (see, Patent Document 1).    Patent Document 1: Japanese Patent Application Publication No. 2004-334107.